"For them to have to deal with third party actors who have a terrorist-type approach changes the nature of that work."
Other countries including the US and Fiji which have larger numbers in Sinai have closed outposts and withdrawn many troops to the south. US military chief General Joseph F. Dunford Jr visited Egypt twice last month because of the deteriorating situation. There are concerns peacekeepers would be targeted as retaliation for efforts to drive out Islamic State in Iraq and Syria.
Peacekeeping troops are only able to fire in self-defence. Mr Brownlee said the Egyptian Armed Forces were battling the terrorist groups and had suffered some casualties. "But in the end where they have a responsibility to provide security for the peacekeepers, it is a bit hard to do both jobs effectively."
Labour's foreign affairs spokesman David Shearer said the Government was taking the right steps in keeping it under review. "I would be hesitant about pulling out our troops completely. I think it also sends the wrong signal if we cut and run. But there's not point having our troops there trying to do a job and being attacked by another group without the means to defend themselves."
He said the mission could make more use of surveillance technology on the border to reduce the need for troops.
New Zealand would have to give six months notice before quitting the mission if it came to that, Mr Brownlee said. "What it indicates is the dead hand of Isil and its death cult approach is causing a bit of rethink here. That rethink is in co-operation with the Egyptians and Israelis, and I would strongly state I have confidence in Egyptian armed forces' ability to contain this particular problem."
Mr Brownlee said the mission was still supported by both Egypt and Israel and the use of technology such as drones could improve security and reduce the need for physical patrols. He had visited south Sinai in April and was satisfied the troops were safe there.